I think it could be hard to do all those things at the same time.
An ipad can control a Presonus Studiolive mixer. If your band have one of those, each band member with an ipad can control his own monitor mix using WIFI.
Check out this mixer it can also record 16/24 tracks(depending on model) while also doing FOH and monitor and is reasonably priced.

I am not sure if the presonus application likes other apps to run in the background, but you could record a click in itunes, play it and send it to the monitor mix. Other band members could use it in their mix too.
Track notes could be done in Word or Excel and transferred to the ipad.

I gig with a singing bass player and he not only uses and iPad as his PDF chart resource, he bought two more so the guitarists and keyboardists he hires would have the same ability.

This really is for free lance musicians that read on a regular basis. The iPad give you both quick access to PDF sheet music and a backlit surface which take the place of a music stand light. He also uses a wireless foot pedal to turn pages.

Pretty cool. He has a large book of tunes he does and the paper versions of each book are quite heavy. This is a solution that makes sense.

There's a great app called ForScore for the iPad. If you need to use charts during a gig, you can scan them in and create set lists in the app. It also has a click so you can read your charts and play to a click at the same time. It also lets you edit the charts and draw on them with your finger if you need to make some quick and dirty edits. Other than that, I use an app called Tempo for a click on gigs where I don't need charts.

There's a great app called ForScore for the iPad. If you need to use charts during a gig, you can scan them in and create set lists in the app. It also has a click so you can read your charts and play to a click at the same time. It also lets you edit the charts and draw on them with your finger if you need to make some quick and dirty edits. Other than that, I use an app called Tempo for a click on gigs where I don't need charts.